This project is designed to evaluate the role of prostaglandins in the pathogenesis and treatment of hemorrhagic shock. The first aim is to determine the effect of prostaglandin on the redistribution of blood flow to various organs during resuscitation from shock. This is being done by means of radioactive microsphere injection. We have shown that prostacyclin (PGI2) selectively increases hepatic blood flow during resuscitation. We plan to evaluate the effect of prostaglandin E1 (PGE1) during the coming year. The second aim of the project is to evaluate the interaction of prostaglandins with synthetic corticosteroids in the treatment of shock and the effects of changing dosage and length of administration of prostaglandin. We will give infusions of prostaglandins for periods of time greater than the one hour infusion previously studied. We will then evaluate the hemodynamic response to the infusion and determine if the increase in cardiac output and fall in systemic and pulmonary vascular resistance is maintained throughout the infusion or if tachyphylaxis occurs. The significance of these studies is that shock and post-shock organ failure remains a major clinical problem and that a better understanding of the role of prostaglandins in its pathogenesis and treatment could perhaps improve survival of injured patients.